MARS HAND LENS IMAGER (MAHLI) INITIAL OBSERVATIONS AT CURIOSITY'S GALE FIELD SITE
Curiosity’s Mars Hand Lens Imager (MAHLI) is a 2-megapixel color camera with a focusable macro lens mounted on a turret at the end of the rover’s 2-m-long robotic arm. MAHLI is designed to focus on targets at working distances of 2.1 cm to infinity; at the minimum distance, in-focus objects are viewed at a resolution of ~14 micrometers per pixel. Instrument capabilities include autofocus, auto-exposure, sub-framing, Bayer pattern color interpolation, lossy (JPEG) and lossless compression, focus merge of up to 8 focus stack images, white light and longwave UV (365 nm) illumination, and 8 GB of aboard-instrument data storage. Robotic arm movement is used to position MAHLI to acquire nested images of increasing spatial resolution, mosaics, and stereo pairs. MAHLI’s main objectives include determining how sedimentary materials in Gale were created, transported, and emplaced; the presence and nature of chemically-precipitated sediments or cements; the nature of depositional and diagenetic environments recorded in these rocks; and the properties of sedimentary materials now absent—those that were eroded from Gale to leave behind the present day Mt. Sharp. Secondary objectives include examination of the clasts comprising regolith fines; documentation of geologic materials subjected to analysis by Curiosity’s other science instruments; and imaging support for rover engineering activities (including the initial robotic arm check-out after arrival on Mars).
The first MAHLI image from Mars was acquired on 7 August 2012; the robotic arm was in the launch/stow position and the MAHLI dust cover was closed. The image showed that a thin film of Martian dust coated the transparent cover during terminal descent. Through that veil is seen a locally flat plain to the north of the rover, covered in angular to sub-angular gravel and pebble-sized clasts, with the north rim of Gale, about 25 km away, in the background.